DK149227B - PRESSURE-RESISTANT END COVER FOR TASKS - Google Patents

Description

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BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a pressure-resistant aluminum end cap with a preformed opening opening in the cover mirror and an annular groove at the transition from the cover mirror to the cover rim for cans containing carbonated beverages, the cover mirror having at least one counterclockwise cover with the cover. inner directed annular bracing groove.

For increasing the pressure resistance of the tire at cans which are under relatively high internal pressure, e.g. with a filling of carbonated beverages, an annular groove is usually formed at the transition from the cover mirror to the cover rim. Furthermore, from US Pat. No. 3,417,989, a completely closed cover is known which has an outwardly curved, annular groove for further reinforcement in the cover mirror.

The increase in the resistance of canisters to internal pressure is, in so far as it is of economic interest, to meet the requirements of a tire pressure resistance by means of covers with less tin thickness.

It is therefore the object of the invention to provide a cover of the kind initially provided with further improved compressive resistance.

The task is solved according to the invention by the pouring opening being substantially about an angle sector relative to the center forming an angle of either 0 * or 90 * with respect to the roll direction of the can, and that the diameter of the stiffening groove is 65% to 80% of the nominal of the can. diameter, preferably 70% - 77% of the nominal diameter of the can.

It has been found that, with increasing internal pressure, a continuous progressive erosion of the cover mirror first appears, which, when overloaded (the pusher strikingly passes into a permanent, directed bulge in the form of a cracking - hereinafter called nasal formation). 30 sedimentation has proved to be a suitable criterion for determining the durability of a tire against internal pressure, and it could be further observed that nasal formation preferably occurs in areas which, relative to the center of the tire, are in an angular sector 'below 45 * relative to the roll direction of the cover sheet, which is obviously related to its rolling texture.

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If the pouring opening is now placed in the region of the 0 * or 90 * sector relative to the rolling direction, and if all the 45 'sectors are cut by a stiffening groove directed towards the inner can, the resistance of the cover to internal pressure is increased by approx. 10%. The end cover is therefore characterized by the one specified in the claim. Thus, in the manufacture of a cover with specific requirements for the pressure resistance, the thickness of the tin can be reduced by the same cover material, which in the present mass production of cans leads to economical, not insignificant material savings.

The pouring opening may be closed with an aluminum sealed tear strip, where the sealing of the tear strip is conveniently done prior to pressing the stiffening groove. However, the pouring opening may also be prefabricated by means of a stamp line, e.g. by a so-called ring-pull closure. In this case 15, the stiffening groove is conveniently pressed before embossing the tear line.

The invention is further explained in the following with reference to the drawing, in which: FIG. 1 is a top view of a cover; FIG. 2 is a cross-section along the line A - A in FIG. 1, FIG. 3 is an enlarged sectional view of FIG. 2 in a stiffening groove; and FIG. 4 is a diagram of the critical bulge pressure (nose formation) depending on the diameter of the brace groove.

The end cover 1 shown is made of aluminum plate with the roller direction X. A pouring opening 2 is positioned with its longitudinal axis in the rolling direction, the longitudinal axis passing through the center of the cover. The end cover is provided with an annular groove 5 for reinforcement at the transition from the planar median surface 3 to the inner casing rim 4. is interrupted at the pouring opening 2. The distance a between the interrupted stiffening groove 6 and the rim of the pouring opening 2 is, e.g. 3 - 5mm. However, this distance a is hardly critical, as one only has to make sure that the direction X through the center, which forms an angle of 45 * with the rolling direction X, is cut completely by the stiffening groove.

To uniquely determine the location of the stiffener 6, its diameter d is set relative to the nominal diameter D of the can body 7. The shape of the stiffener groove 6 is determined by radius of curvature r and depth t.

Example

Of an aluminum alloy of mainly 2.8% magnesium and 0.3% manganese, a canopy thickness of 0.33 mm was made for cans with a nominal diameter of 63 mm. At the transition from the planar surface to the cephalic rim, an annular groove was formed with a depth of 1.7 mm and a radius of 0.8 mm. In the roll direction of the tin, a pouring opening was punched onto which was sealed an aluminum tear strip, after which a stiffening groove according to the invention was pressed with a cross section depth of 1.0 mm and with a cross section radius of 1.0 mm.

the covers were folded on can bodies. Through a coupling piece located in the wall of the can body, the internal pressure was continuously increased by compressed air until a nasal formation occurred. The nasal formation now took place in the region between the interrupted stiffening groove and the edge of the pouring opening, and thus not, as before, in a direction which forms an angle of 45 * with respect to the rolling direction. The critical bulge pressure at which a nasal formation occurs strikingly is shown in FIG. 4 depicted depending on the ratio d / D for different diameters of the stiffening groove in canister covers with a nominal diameter of 63mm. The diagram shows that by means of the stiffening groove, a tire's resistance to internal pressure can be increased by more than 10%. 1